I get that they were young doctors, in a tough spot with childcare. But the answer really isn’t to hire and exploit an aupair. I would expect someone who needed a round the clock on call childcare provider (which is what you’d need to cover those bunking in the hospital 4am issues you mention) to hire a very well paid nanny with experience of baby care and used to/expecting odd hours.
It really annoys me that people think they can get a proxy parent/full time nanny for aupair money. It is just very unfair and exploitative. Nannies generally are well paid and will have an employment contract, aupairs are ‘helpers’ who are paid pocket money.
@Kanaloa
It's not so in the US.
Au pairs are a cultural exchange programme. You get students hoping to learn English, perhaps as part of degree requirements. They do some childcare, some housework, some cooking, depending on their preference and the needs of their host family.
Nannies are basically people who are doing a stint in childcare before something else turns up. I know one exception, a woman with a BA from a very respected university, in her early 40s now, who earns what a teacher with about five years experience would make. She lives with a family, goes with them on vacations, has her own suite in their mansion. No marriage, no kids of her own. It is a very, very odd career choice.
There simply are not Norland standard nannies going a begging with experience, willingness to live in, etc in the US. Not for the sort of money young doctors make. You might find them in Hollywood or some parts of NYC.